i tend to call these things by which works i'd be proudest of if i were the composer - couldn't limit it to 5 if i muddied the waters with his body of work as a beatle, so just drawing from his solo years.
- remember (possibly the most singularly, persistently haunting of lennon's 'childhood flashback' songs)
- john sinclair (hard white panther agitprop)
- aisumasen (i'm sorry) (nothing else quite like this one in the lennon canon, tortured, slow-crawling blues lament with some interesting changes, not the straight eight for a blues)
- old dirt road - scared - #9 dream (i could have chosen two or three more from 'walls and bridges', amazing album)
although clearly unfinished, i was always fond of 'mucho mungo', too.